Replace NimBLEAttValue asserts with user defineable action.

* Adds the NIMBLE_CPP_DEBUG_ASSERT macro that calls a weak function to allow user defined action, defaults to critical error message and aborts.
* Adds a config option to disable asserts using the NIMBLE_CPP_DEBUG_ASSERT macro.

Kconfig

@@ -69,4 +69,11 @@ config NIMBLE_CPP_ATT_VALUE_INIT_LENGTH
         characteristic or descriptor is constructed before a value is read/notifed.
         Increasing this will reduce reallocations but increase memory footprint.
 
+config NIMBLE_CPP_DEBUG_ASSERT_ENABLED
+    bool "Enable debug asserts."
+    default "n"
+    help
+        Enabling this option will add debug asserts to the NimBLE CPP library.
+        This will use approximately 1kB of flash memory.
+
 endmenu

src/NimBLEAttValue.h

@@ -42,7 +42,6 @@
 #    error CONFIG_NIMBLE_CPP_ATT_VALUE_INIT_LENGTH cannot be less than 1; Range = 1 : 512
 #endif
 
-
 /* Used to determine if the type passed to a template has a c_str() and length() method. */
 template <typename T, typename = void, typename = void>
 struct Has_c_str_len : std::false_type {};
@@ -267,7 +266,8 @@ public:
 
     /** @brief Subscript operator */
     uint8_t operator [](int pos) const {
-        assert(pos < m_attr_len && "out of range"); return m_attr_value[pos]; }
+        NIMBLE_CPP_DEBUG_ASSERT(pos < m_attr_len);
+        return m_attr_value[pos]; }
 
     /** @brief Operator; Get the value as a std::vector<uint8_t>. */
     operator std::vector<uint8_t>() const {
@@ -312,7 +312,7 @@ public:
 
 inline NimBLEAttValue::NimBLEAttValue(uint16_t init_len, uint16_t max_len) {
     m_attr_value   = (uint8_t*)calloc(init_len + 1, 1);
-    assert(m_attr_value && "No Mem");
+    NIMBLE_CPP_DEBUG_ASSERT(m_attr_value);
     m_attr_max_len = std::min(BLE_ATT_ATTR_MAX_LEN, (int)max_len);
     m_attr_len     = 0;
     m_capacity     = init_len;
@@ -355,7 +355,7 @@ inline NimBLEAttValue& NimBLEAttValue::operator =(const NimBLEAttValue & source)
 
 inline void NimBLEAttValue::deepCopy(const NimBLEAttValue & source) {
     uint8_t* res = (uint8_t*)realloc( m_attr_value, source.m_capacity + 1);
-    assert(res && "deepCopy: realloc failed");
+    NIMBLE_CPP_DEBUG_ASSERT(res);
 
     ble_npl_hw_enter_critical();
     m_attr_value   = res;
@@ -390,7 +390,7 @@ inline bool NimBLEAttValue::setValue(const uint8_t *value, uint16_t len) {
         res = (uint8_t*)realloc(m_attr_value, (len + 1));
         m_capacity = len;
     }
-    assert(res && "setValue: realloc failed");
+    NIMBLE_CPP_DEBUG_ASSERT(res);
 
 #if CONFIG_NIMBLE_CPP_ATT_VALUE_TIMESTAMP_ENABLED
     time_t t = time(nullptr);
@@ -425,7 +425,7 @@ inline NimBLEAttValue& NimBLEAttValue::append(const uint8_t *value, uint16_t len
         res = (uint8_t*)realloc(m_attr_value, (new_len + 1));
         m_capacity = new_len;
     }
-    assert(res && "append: realloc failed");
+    NIMBLE_CPP_DEBUG_ASSERT(res);
 
 #if CONFIG_NIMBLE_CPP_ATT_VALUE_TIMESTAMP_ENABLED
     time_t t = time(nullptr);

src/NimBLEDevice.cpp

@@ -1259,4 +1259,16 @@ void NimBLEDevice::setCustomGapHandler(gap_event_handler handler) {
 
 } // setCustomGapHandler
 
+#if CONFIG_NIMBLE_CPP_DEBUG_ASSERT_ENABLED || __DOXYGEN__
+/**
+ * @brief Debug assert - weak function.
+ * @param [in] file The file where the assert occurred.
+ * @param [in] line The line number where the assert occurred.
+ */
+void nimble_cpp_assert(const char *file, unsigned line) {
+    NIMBLE_LOGC("", "Assertion failed at %s:%u\n", file, line);
+    abort();
+}
+#endif // CONFIG_NIMBLE_CPP_DEBUG_ASSERT_ENABLED
+
 #endif // CONFIG_BT_ENABLED

src/nimconfig.h

@@ -32,6 +32,18 @@
 #  endif
 #endif
 
+#if CONFIG_NIMBLE_CPP_DEBUG_ASSERT_ENABLED && !defined NDEBUG
+void nimble_cpp_assert(const char *file, unsigned line) __attribute((weak, noreturn));
+# define NIMBLE_ATT_VAL_FILE  (__builtin_strrchr(__FILE__, '/') ? \
+                            __builtin_strrchr (__FILE__, '/') + 1 : __FILE__)
+# define NIMBLE_CPP_DEBUG_ASSERT(cond) \
+    if (!(cond)) { \
+        nimble_cpp_assert(NIMBLE_ATT_VAL_FILE, __LINE__); \
+    }
+#else
+# define NIMBLE_CPP_DEBUG_ASSERT(cond) (void(0))
+#endif
+
 #endif /* CONFIG_BT_ENABLED */
 
 #ifdef _DOXYGEN_